From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:47172) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S5vF4-00067R-7l for qemu-devel@nongnu.org; Fri, 09 Mar 2012 03:32:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S5vEy-0002Q5-0d for qemu-devel@nongnu.org; Fri, 09 Mar 2012 03:32:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37171) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S5vEx-0002Pv-OQ for qemu-devel@nongnu.org; Fri, 09 Mar 2012 03:31:55 -0500 Message-ID: <4F59BFE3.4070907@redhat.com> Date: Fri, 09 Mar 2012 09:31:31 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1331226917-6658-1-git-send-email-pbonzini@redhat.com> <1331226917-6658-15-git-send-email-pbonzini@redhat.com> <20120309082041.GA28158@puku.stupidest.org> In-Reply-To: <20120309082041.GA28158@puku.stupidest.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 14/17] block: support FALLOC_FL_PUNCH_HOLE trimming List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Chris Wedgwood Cc: qemu-devel@nongnu.org Il 09/03/2012 09:20, Chris Wedgwood ha scritto: > for preallocated files this will punch holes all over the place and > reallocation will cause fragmentation (guests will free and reallocat > blocks normally) SEEK_HOLE could provide a very simple heuristic to detect preallocated files (unfortunately ext4 does not implement SEEK_HOLE yet). > xfs has a mechanism to convert to unwritten extents that would avoid > that, but it's not implemented in other filesystems Interesting, thanks! Paolo